Fluid-translating device



H. F. SCHMIDT.

FLU-19 mmsurms DEVICE.

APPLICATIO FILEDSEPT. 34, I914.

Patented Mar. 9, 1920.

IN VE N TOR.

WITNESSES.

T m F W Y 5 M o T T A w H HENRY F. SCHMIDT, 0F PITTSBURGH, PENNSYLVANIA,

ASSIGNOER T0 WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

FLUID-TRANSLATING DEVICE.

Specification of Letters Patent.

Patented Marie, 1920.

Application filed September 14, 1914. Serial No. 861,639.

To all whom it may concern Be it known that I, HENRY F. SoHMIo'r, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania. have made a new and useful Inventlon in Mid-Translating Devices, of which the following is a specification.

This invention relates to nozzles and particularly to nozzles for delivering the expelling fluid or medium to the workinv passages of fluid translating devices of the kinctic' type, such for example as ejectors.

An object of the invention is to reduce improved means for gradually acce crating the f'luid or medium to be ejected or compressed, to the velocity of the expelling fluid or medium.

A further object is to produce a fluid expanding nozzle in which means are employed for automatically varying the effective discharge area with relation to the throat area in response to variations in the initial and final pressures over which the nozzle operates, thereby avoiding losses resulting from under expansion when the outlet area is too small and resulting from shock due to over expansion and recompression when the outlet area is larger than that necessary.

" These and other obects, which will be made apparent throng out the further description of the invention, are attained by means of nozzles or ejecting devices employingthe features herein described and illus trated in the drawings accompanying and forming a part of this application.

In the drawings Figure 1 is a diagrammatic fragmental .ectional view of an e ector equipped with a series or nozzles embodying my IIIVBIIiDlOIL Fig. 2 is a similar view of an ejector equipped with a series of nozzles embodying a modification of my invention.

Figf 3 is a similar View of an ejector equipped "with a nozzle embodying a modification of my invention, in which means are employed for varying the ratio ofthe effective outlet area with relation to the inlet area, of the nozzle, in response to variations in the initial or in the. final pressure to whichlthef nozzle is subjected and Fig, 4 is an enlarged sectional viewf th nozz eshown in 3, in connectionwith a v tar -a r new ea eg?Lann e?P known principle that the of operation of the nozzle shown as an embodiment of the invention in Fig. 3.

Fig. 5 is a sectional view on a reduced scale along the line 5-5 of Fig. 1.

Referring to Fig. 1, the apparatus illustrated consists of a combining or suction chamber 5, to which fluid to be ejected is delivered through a port 6, and which comll'lLll'ilCttiTBS with a diffuser 7 shown broken away for convenience of illustration. A series of fluid delivery nozzles is shown extending into-the chamber 5 and communicating with a pressure chamber 8, which receives fluid under pressure from any suitable source through a port 9. Each of the nozzles communicating with the chamber 8 is provided with a divergent mouthpiece. but the nozzle ratio of the different nozzles is varied in accordance with the osition of the nozzle in the chamber 5. l3 nozzle ratio I mean the efi'ective area of tie outlet of the nozzle divided by the effective area of the nozzle throat or of the most contracted cross section of the nozzle. It is a well known principle of mechanics that the momentum after the im act of two bodies, is equal to the sum of the momenta of the two bodies before impact. It is also a well loss ofkinetic energy, resulting from the shock when two bodies moving at different velocities collide, increases with the difference in the velocity of the two bodies prior to the collision. For these reasons an object of my invention is the production of a series of nozzles for entraining the fluid or liquid to be ejected, such that the velocity of the fluid to be entrained is gradually increased to a velocity near that of the entraining or expelling medium.

One of the' fundamental conditions in ejectors is thatthe medium to be expelled or ejected is practically at rest, w ereas the expelling medium is moving at a high velocity. A mixture of these two mediums will occasion considerable loss in energy and to reduce the loss, I contemplate gradually increasing the velocity of the fluid to be expelled by subjecting it to the action of relatively small streams of expelling fluid prior to bringing it in contact with t e main and relatively large stream of expelling fluid.

In Fig. 1,1 have shown an arrangement of nozzles consisting of a main expelling nozzle 1.0,whic'h is "surrounded by an annular series of shorter nozzles 11. These nozzles are preferably inclined inwardly toward the nozzle 10 so that the fluid discharged by them is more readily capable of uniting with the stream of flu1d discharged from the nozzle 10 to form a single stream. I have also shown an annular series of nozzles 12 around the nozzles 11 which, like the nozzles 11., are inclined 1nwardl or toward the nozzle 10, and wh ch are a apted to discharge jets of fluid mwardly toward the jet ischarged from nozzle 10. These nozzles 12 are shorter than the nozzles 11 and it is desirable, although not essential, to so space the nozzles in each of the annular series that the fluid discharged by the nozzles of each series forms a substantially annular stream. This spacing is illustrated in Fig. 5. All of the nozzles 10, 11 and 12 have the same expansion ratio, but the nozzles 11 are so roportioned that each discharges a relatively small amount of fluid as compared with the amou" t of fluid discharged by the nozzle 10, and each nozzle 12 is so proportioned that it discharges a smaller quantity of fluid than is discharged by any one of the nozzles 11.

With this arrangeme t the fluid or medium to be ejected and existin in the chamber 5, is first subjected to t e action of the fluid issuin from the nozzles 12, and the entraining e ect of this fluid imparts initial velocity to the medium to be ejected. As the medium, so entrained, moves toward the throat of the diffuser 7 it is successively subjected to the entraining effect of the fluid discharged by the nozzles 11 and by the nozzle 10 so that its velocity is gradually increased as it moves from the chamber 5 into the throat of the diffuser 7. By thus gradually increasing the velocity of the medium to be ejected or entrained, the loss in energy is materially reduced over that encountered in ordinary ejectors, since the difference between the velocity of the entrained medium and main expelling jet is materially reduced at the'time the entrained medium is subjected to the action of the main ex elling jet. The loss of energy, occasione 'y the shock resulting from the entraining of the medium to be ejected by the jets delivered from the nozzles 12, is relatively small as compared with the available energy of all the nozzles, and the same is true of the loss occasioned by the entrainment ofthe medium by the jets dischar 'ng from the nozzles 11', consequently the e ciency of the organized agparatus 1S materially higher than the e ciency of ejector nozzles ordinarily emloyed, in which no means areutilized .for imparting velocity to the medium prior to subjecting it to the action of the main expolling jet.

the velocity of the charged from the When it is remembered that the medium existing in the chamber 5 is ordinarily in a hi her rarefied state, stoo that considerable difliculty is encoum tered in entraining it since, if the main expelling jet is spread so as to increase its entraining area, its elficiency is materially reduced by reason of the fact that it must be recombined before throat of the diffuser. In order to o viate the loss occasioned by spreading or subdividing the main expelling 'ets to obtain sufficient entrainin area, an at the. same time to obtain su cient entraining area, I provide nozzles which discharge relatively small amounts of motive fluid or steam as compared with the .motive fluid or steam disc arged by the main expelling nozzle and I so construct these smaller nozzles that the steam discharged by them is under or incompletely expanded. With this ari'angement a relatively small quantity of steam is in effect exploded as it issues from its discharge nozzles, thereby ex; anding or spreading out so that the entr ining area of the combined jets discharg b all of the nozzles is materially increased, while the velocity and inte rity of the major portion of the jet is una ected.

In Fig. 2, I have shown an arrangement of nozzles for accomplishing this. The apparatus illustrated in Fig. 2 consists of a suction or combining chamber 5', which communicates with a port 6' and a diifuser 7, and into which a series of nozzles, comprisin a central nozzle 13, an annular series o nozzles 14, and an annular series of nozzles 15, project. The central nozzle 13 is referably located concentrically with relation to the diffuser 7', and the nozzles 14, like the nozzles 11, surroundthe central nozzle, but are shorter than the central nozzle and have a smaller nozzle ratio. The nozzles 15 are shorter than the nozzles'la and have a smaller nozzle ratio than these nozzles. As in Fig. 1, the nozzles of each. annular series are inclined inwardly toward the central -nozzle and they are preferably so arranged that the se arate jets discharged by them unite to orm an annular jet. The fluid issuing from the nozzles 15 15 under or incom letely expanded and consequentl is ,capa le of expandin freely within t e chamber 5 after it issuesgromlthe nozzles. This free expansion causes it to expander spread by the formation of eddies along the boundary of the jet, and conse quently increases its efliciency as an entraining agent. The same is true of the jets disnozzles 14, although the ratio of expansion of these nozzles is greater and consequently the free expansion ofthd fluid issuin from them is somewhat dimin ished, but is e velocit of the fluid is higher so;-that the entrain it will be under;

passing throu h the fluid is. gradually ass celerated as it passes toward the jet discharged from the nozzle 13 and is sub ccted, first to the action of the jets issuing from the nozzles 15 and then to the action of the jets issuing from the nozzles 14. The nozzle or expansion ratio of the central nozzle 13 is such that the fluid issuing from it is .expanded to the pressure normally existing in the chamber 5', consequently the jet oi fluid discharged by it has the maximum velocity possible under the existing operat ing conditions and passes through the diffuser with a minimum loss of energy.

By so proportioning the ellective areas of the nozzles 1-1 and 15, relatively to the efl'cctive area of the nozzle 13, the major portion of the steam forming the combined jet traversing the diffuser may be discharged from the nozzle 13, and consequently the losses occasioned by the free expansion, for the purpose of increasing the entraining ciliciency of the jet, will be comparatively small.

If desired, the effective areas of the nozzles 1.4 and 15 can be proportioned as described in connection with the nozzles 12 and 11 in Fig. 1, or a combination of the apparatus disclosed in Figs. 1 and 2 may be employed for the purpose of obtaining the advantages inherent in each apparatus.

In Fig. 3, I have shown an ejector employed with a central nozzle 16, which is provided at points along its divergent mouth piece with annular series of ports 17, which are more clearly illustrated in the cross sectional view forming part of Fig. 4. These ports 17 are located between the throat of the nozzle and the outlet 18 and establish communication between the interior of the nozzle and the space into which the nozzle discharges.

In Fig. 4, I have shown a modification 16 of the nozzle 16 having annular series of orts 1T corresponding to the ports 1'4 of ig. 3.

With this arrangement the nozzle ratio is automatically varied for variations in operatin conditions; that is, pressure variations in the pressure chamber-.8", or pressure variations in the chamber 5", or at the outlet 18 of the nozzle.

In Fig. 4 I have shown pressure diagrams illustrating the operation of the nozzle under the varying conditions and also the operation of an ordinary form of nozzle which does not embody my invention when it is subjected to conditions other than those for which it was designed. The pressure diagram is shown in connection with the crosssection of a nozzle embodying my invention in such a manner that the pressures at various parts on the diagram correspond to those which would obtain in a nozzle such as that illustrated. In the pressurediagram expandible fluid is admitted to the nozzle is designed.

1.6 at a pressure A in the diagram and in traversing the nozzle expands along the pressure line ADB to the lower pressure B for which the outlet area 18 of the nozzle Now, should the lower pressure to which the nozzle must expand be increased to a pressure C indicated by the line CH on the diagrarma nozzle not fitted with the openings, as shown in the nozzle illustrated, would expand the steam to some pressure, such as D, below the line HC (that is, over expand) and then, owing to the fact that the area of the divergent mouth piece is larger than necessary for expansion to the pressure C, compression shocks, as indicated by the dot-dash line at F, would occur within the nozzle, recompressing the medium to the pressure C, at which it would be discharged from the nozzle outlet 18*. The compression shocks would, however, cause a serious loss of energy in the nozzle, and the velocity with which the medium would leave the outlet of the nozzle would be considerably below that which it would have acquired in expanding from the pressure A to the pressure 0 in a nozzle properly propor tioned for such an ex ansion.

By employing the illerent series of holes 17 in the nozzle, as shown in Fig. 4, the medium in the space surrounding the nozzle into which the latter discharges can enter the nozzle at different positions along its mouth piece. Thus, with a nozzle so formed, the medium when ex )anding from a pressure A to a pressure if would expand along the line AME, the pressure at the point E falling slightly below the pressure C, and slight recompression shocks would occur in the nozzle beyond the point E, but these would be of comparatively slight extent and would result in comparatively slight losses, due to the fact that when the pressure beyond the point M tends to fall below that in the space surrounding the nozzle, medium from outside the nozzle flows from the holes 17, as indicated in Fig. 4 by shaded lines within the nozzle, forming a moving filler which extends, from that point in the nozzle where the pressure falls to that of the s )ace surrounding the nozzle to the mouth 0 the nozzle. This, in effect, reduces the area of the outlet of the nozzle to that of the mouth piece at the point at which the pressure falls to that of the surrounding medium, or the pressure 0.

If, however, the pressure to which the nozzle 16, fitted with holes 17, expands, is a pressure B, the pressure at every point in the nozzle being above B, none of the medium surrounding the nozzle will enter the holes 17, but escape of medium from within the nozzle to the surrounding space is very largely, if not entirely. prevented by the slope of the holes 17, which is in the direction of flow in the nozzle. Thus it will be &

. into the chamber The means illustrated consists of'a chamber incloscd by a Wall 21 and which surrounds the nozzle and communicates with the outer ends of the openings 17. The wall is provided with one or more ports 22, each ofwhich is controlled by a c eck or flap valve 23, which in turn is controlled-by a spring 24, and is arranged to permita flow of fluid or medium into but to prevent a flow of medium from the chamber. t will be understood that the drawing is mere] illustrative, that the wall 21 extends entire y around the nozzle and that each annular series of openings may be segregated by a separate annular wall and be provided with a separate controlling .valve 23.

While there is, of course, some loss of 7 energy in the nozzle, due to the mixture of high velocity and low velocity medium, the loss so resulting is considerably less than the loss of energy which results from the recompression shock in a nozzle not equipped with the filling holes 17.

In my copending'application Serial No. 861,630, filed September 14, 1914, and entitled Fluid translating devices, I have disclosed and claimed an ejector in which means are provided for varying the effective area of a nozzle'of the ejector in -accordance with variations in the amount of fluid to be ejected, and in Which means are provided for varying the expansion ratio of the nozzle. The e ector described and illustrated is provided with a needle valve which extends through the steam inlet chamber into the throat of the nozzle and is controlled by a piston subjected on one side to the pressure of the fluid entering the ejector, and on the other side to the pressure of thefluids passing through the diffuser. Variations in the difierential pressure acting on the piston cause the needle valve to move into or out of the nozzle, thereby changin the effective area and expansion ratio of t is nozzle,

In my copending application for Fluid translating devices, Serial No. 861,631, filed Sept. 14, 1914, I have disclosed and claimed an ejector in which the main nozzle is surrounded by accelerating nozzles, the flow of motive fluid to the accelerating nozzles being *controlled by means responsive to variations in amount of the fluid to be ejected, the position of the main nozzle being controlled by the saline means. The position of the main nozzle is controlled by a piston subjected on one side to the pressure of the fluid to be ejected, and on the other side to the pressure of the fluids passing through the 618M301. The main nozzle is provided with a tubular extension in which are ports for controlling the flow of motive fluid to the accelerating nozzles.

In my copending application for Fluid translating devices, Serial No. 861,633, filed September 14, 1914, I have disclosed and claimed an ejector in which means are pro vided for varying the efi'ective area and po-' sition of the throat of a diffuser. Several embodiments of the invention are disclosed but in all of them the nozzle is moved in relation to the difl'user by means of a piston exposed on one side to the pressure of the fluid to be ejected, and on the other side to the pressure of the fluids in the diii'user. The nozzle may become substantially an e tension to the diffuser thereby changing t effective area and throat of the diffuser.

It will, of course, be understood that a nozzle embodying the features illustrated in connection with the nozzle 16 may be employed as the central nozzle in apparatus,

embodying the features illustrated in either Figs. 1 M2, or in apparatus embodying the features illustrated in both Figs. 1 and i It Will also be understood that the shorts or accelerating nozzles of either Figs. 1 or 2 may be equi ped with filler apertures for admitting a uid sheath of the medium surrounding the nozzle, and that my invention contemplates an apparatus embodying the features of the apparatus illustrated in Figs. 1, 2 and 3.

What I claim is:

1. In combination in an apparatus of the character described, a chamber having an inlet port through which medium to be translated is admitted, means for expelling medium from said chamber, and for gradually accelerating the medium in the chamber, comprising groups of nozzles of different lengths, and of difi'erent areas, the outer groups of nozzles having successively smaller areas than the inner groups.

2. In combination in an apparatus of the character described, a chamber having an inlet port through which medium to be expelled is admitted, and means for gradually accelerating and expelling the medium from the chamber, comprising concentric rows of nozzles of difi'erent'lengths, and of different areas and expansion ratios, the shorter nozzles being located at the outer edge of the group and having the smaller areas and the smal r expansion ratios.

3. In combination m an apparatus of the character described, a chamber having a port through which medium to be expelled is delivered, means for admitting an expelling fluid to said chamber, and for gradually accelerating the medium in the chamber to substantially the velocity of the fluid, by means of groups of nozzles having difi'erent expansion ratios.

4. In combination in an apparatus of the character described, a chamber having a port for admitting medium to be expelled, means for delivering and expelling fluid to said chamber, and for increasing the entraining efi'ect of the fluid delivered, comprising nozzles of difi'erent areas and difi'erent expansion ratios.

5. In combination in an apparatus of the character described, a chamber havin a port for admittingtmedium to be expel ed,

-means for admitting a jet of expelling fluid to said chamber, and accelerating or entraining nozzles for delivering fluid to said chamber so proportioned as to cause free expansion of the fluid within the chamber.

6. In combination in an apparatus of the character described, a chamber having a port throu h-which medium to be expelled is admitte an accelerating nozzle for delivering a jet of fluid to said chamber, so formed. as to cause a free expansion of the fluid in the chamber, in combination with a nozzle for delivering expelling fluid to said chamber so formed as to completely expand the fluid delivered thereby to the normal Working pres sure of the chamber.

7. In combination in an apparatus of the character described a chamber, a nozzle for expanding expelling fluid delivered to the chamber and having means for varying the effective discharge area thereof in response to variations in the initial or final pressure of the fluid being expanded.

8. In combination in an apparatus of the character described, an expansion nozzle having means for varying its expansion ratio inresponse to variations in the initial or final pressure of the fluid passing there, through.

9. In combination in an apparatus of the character described, a chamber, from which medium is to be expelled, a nozzle for eX pending and delivering expelling fluid to the chamber, having means for varying the expa nsion ratio in response to variations in the initial or final pressure of the fluid, by admitting fluid from said chamber through filler openings along the nozzle.

10. A fluid discharge nozzle having a mouth piece divergent toward the outlet provided with openings located intermediate the inlet and outlet ends thereof for admitting or discharging a small quantity of fluid to or from the nozzle in response to variations in the difference in pressure between the inlet and outlet ends thereof.

11. A fluid nozzle having openings along the mouth iece thereof, and means for mitting a ow of fluid through the openings into the nozzles, but for preventing a flow of fluid through the openings from the nozzle.

In testimony whereof, I have hereunto subscribed my name this 21st day of August, 1914.

HENRY F. SCHMIDT.

Witnesses C. W. MGGHEE, E. W. MGGALLISTER. 

